Managers are expected to brief staff about the consultation later today. Between 500 and 1,000 posts are thought to be at risk, although precise numbers have not been announced.

The move at the company, which employs about 23,000 people worldwide, comes as part of a major restructuring exercise.

It is now thought that about 25 directors, several of them ex-BAA staff, have left company the firm in the past several days.

Last week Contract Journal revealed that Britain’s biggest private contractor was reorganising its management structure to concentrate on flourishing sectors such as education, energy/nuclear, waste and transport/rail.